@ManyToMany
@JoinTable(
  name="visit_zones",
  joinColumns=@JoinColumn(name="visit_id"),
  inverseJoinColumns={
    @JoinColumn(name="zone_id", referencedColumnName="zone_id"), 
    @JoinColumn(name="zone_version", referencedColumnName="version")
  }
)	
public Set<Zone> getZones() {
	return zones;
}